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PHP character encoding conversion from gb2312 to utf8_PHP tutorial

WBOYOriginal: 2016-07-13 10:48:17856browse

In character encoding conversion in PHP, we generally use iconv and mb_convert_encoding to operate, but the conversion performance of mb_convert_encoding is much worse than iconv.

string iconv ( string in_charset, string out_charset, string str )
Note: In addition to specifying the encoding to be converted to, the second parameter can also add two suffixes: //TRANSLIT and //IGNORE, where //TRANSLIT will automatically convert characters that cannot be directly converted into one or more Approximate characters, //IGNORE will ignore characters that cannot be converted, and the default effect is to truncate from the first illegal character.
Returns the converted string or FALSE on failure.

string mb_convert_encoding ( string str, string to_encoding [, mixed from_encoding] )
You need to enable the mbstring extension library first, and remove the ; in front of extension=php_mbstring.dll in php.ini
mb_convert_encoding can specify multiple input encodings. It will automatically identify based on the content, but the execution efficiency is much worse than iconv;

Use:

It was found that iconv would make an error when converting the character "-" to gb2312. Without the ignore parameter, all strings following this character cannot be saved. No matter what, this "—" cannot be converted successfully and cannot be output. In addition, mb_convert_encoding does not have this bug.

In general, use iconv. Only use the mb_convert_encoding function when you are unable to determine what the original encoding is, or when iconv cannot be displayed normally after conversion.

The code is as follows

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代码如下

复制代码

/**
*自动判断把gbk或gb2312编码的字符串转为utf8
*能自动判断输入字符串的编码类，如果本身是utf-8就不用转换，否则就转换为utf-8的字符串
*支持的字符编码类型是：utf-8,gbk,gb2312
*@$str:string 字符串
*/
function yang_gbk2utf8($str){
    $charset = mb_detect_encoding()($str,array('UTF-8','GBK','GB2312'));
    $charset = strtolower($charset);
    if('cp936' == $charset){
        $charset='GBK';
    }
    if("utf-8" != $charset){
        $str = iconv($charset,"UTF-8//IGNORE",$str);
    }
    return $str;
}

/**

* Automatically determine and convert gbk or gb2312 encoded strings to utf8

*Can automatically determine the encoding type of the input string. If it is UTF-8, there is no need to convert it. Otherwise, it will be converted to a UTF-8 string

*Supported character encoding types are: utf-8, gbk, gb2312

*@$str:string string

代码如下	复制代码
$str="测试ing"; $cha=mb_detect_encoding($str); echo $cha; ?>

function yang_gbk2utf8($str){

$charset = mb_detect_encoding()($str,array('UTF-8','GBK','GB2312'));

$charset = strtolower($charset);

If('cp936' == $charset){

代码如下	复制代码
$str="测试ing"; $cha=mb_detect_encoding($str); $s = iconv($cha,"UTF-8",$str); var_dump($s); ?>

$charset='GBK'; } If("utf-8" != $charset){ $str = iconv($charset,"UTF-8//IGNORE",$str); } Return $str; }

Now I will look at some problems in converting character encoding Use the mb_detect_encoding($str); function. To use this function, you must open the php extension=php_mbstring.dll extension

The code is as follows	Copy code
$str="Testing";<🎜> $cha=mb_detect_encoding($str);<🎜> echo $cha;<🎜> ?>

I entered it on the gb2312 page, but the output result is UTF-8, which is very strange, and I haven’t found the reason yet. I want to uniformly convert to UTF-8 encoding, use the following method

The code is as follows	Copy code
$str="Testing";<🎜> $cha=mb_detect_encoding($str);<🎜> $s = iconv($cha,"UTF-8",$str);<🎜> var_dump($s);<🎜> ?>

Result returned:
string(0) “”
It's really strange why this happens.
Use

The code is as follows	Copy code

代码如下	复制代码
$str="测试ing"; $cha=mb_detect_encoding($str); $s = iconv("GB2312","UTF-8",$str); var_dump($s); ?>

$str="Testing";

$cha=mb_detect_encoding($str);
$s = iconv("GB2312","UTF-8",$str);
var_dump($s);
?>

代码如下	复制代码
$a="我很好"; echo mb_convert_encoding ($a,'UTF-8'); ?>

The returned result is correct. It is found that the function mb_detect_encoding($str); is still inaccurate. I don't know why.

Function string mb_convert_encoding ( string $str , string $to_encoding [, mixed $from_encoding ] )

Can be converted to a string with a specified encoding, I wrote an example

The code is as follows

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$a="I'm fine";

echo mb_convert_encoding ($a,'UTF-8');
?> 

	  
		 代码如下
		复制代码
	  
	  
		
$str=chr(254)."测试ing".chr(254);

$s = iconv("GB2312","UTF-8",$str);

var_dump($s);

?>

The result is: ??枞?枞? The question now is if I convert different string encodings to UTF-8, can I use iconv if I know the change in advance? But what should I do if I don’t know the encoding? Problem 3: iconv problem, if the encoding of the first byte of the converted string is greater than a certain number, null will be returned. For example:

The code is as follows	Copy code
$str=chr(254)."Testing".chr(254);<🎜> $s = iconv("GB2312","UTF-8",$str);<🎜> var_dump($s);<🎜> ?>

Return
string(0) “”

For the usage of mb_convert_encoding, please see the official website:

http://cn.php.net/manual/en/function.mb-convert-encoding.php

Another function iconv in PHP is also used to convert string encoding, and its function is similar to the function above.

There are some detailed examples below:
iconv — Convert string to requested character encoding
(PHP 4 >= 4.0.5, PHP 5)
mb_convert_encoding — Convert character encoding
(PHP 4 >= 4.0.6, PHP 5)

Usage:
string mb_convert_encoding ( string str, string to_encoding [, mixed from_encoding] )
You need to enable the mbstring extension library first, and remove the ; in front of extension=php_mbstring.dll in php.ini
mb_convert_encoding can specify multiple input encodings. It will automatically identify based on the content, but the execution efficiency is much worse than iconv;

string iconv (string in_charset, string out_charset, string str)
Note: In addition to specifying the encoding to be converted to, the second parameter can also add two suffixes: //TRANSLIT and //IGNORE, where //TRANSLIT will automatically convert characters that cannot be directly converted into one or more Approximate characters, //IGNORE will ignore characters that cannot be converted, and the default effect is to truncate from the first illegal character.
Returns the converted string or FALSE on failure.

Use:
It was found that iconv would make an error when converting the character "-" to gb2312. Without the ignore parameter, all strings following this character cannot be saved. No matter what, this "—" cannot be converted successfully and cannot be output. In addition, mb_convert_encoding does not have this bug.
Under normal circumstances, use iconv. Only use the mb_convert_encoding function when you cannot determine what the original encoding is, or when iconv cannot be displayed normally after conversion.

from_encoding is specified by character code name before conversion. it can be array or string – comma separated enumerated list. If it is not specified, the internal encoding will be used.
/* Auto detect encoding from JIS, eucjp-win, sjis-win, then convert str to UCS-2LE */
$str = mb_convert_encoding($str, “UCS-2LE”, “JIS, eucjp-win, sjis-win”);
/* “auto” is expanded to “ASCII,JIS,UTF-8,EUC-JP,SJIS” */
$str = mb_convert_encoding($str, “EUC-JP”, “auto”);

Example:

The code is as follows

代码如下	复制代码
$content = iconv("GBK", "UTF-8", $content); $content = mb_convert_encoding($content, "UTF-8", "GBK"); ?>

Copy code

$content = iconv("GBK", "UTF-8", $content);

代码如下	复制代码
function phpcharset($data, $to) { if(is_array($data)) { foreach($data as $key => $val) { $data[$key] = phpcharset($val, $to); } } else { $encode_array = array('ASCII', 'UTF-8', 'GBK', 'GB2312', 'BIG5'); $encoded = mb_detect_encoding($data, $encode_array); $to = strtoupper($to); if($encoded != $to) { $data = mb_convert_encoding($data, $to, $encoded); } } return $data; } ?>

$content = mb_convert_encoding($content, "UTF-8", "GBK"); ?>

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